Quite a lot

After a Lengthy Discussion with the Mizūkage John was allowed into the Village as a Shinobi of the Mist, the Mizūkage also revealed that the Swords he had found were one seventh of the Mists Legendary Seven Ninja Swordsmen's Blades, they were the legendary Kiba, or Fangs, and they were imbued with Lightning-Style Chakra during their Creation to increase their Sharpness and Cutting Power, and to induce a numbing affect when cutting something or someone. And since The Mist had only recently regained several Swords such as the Shibuki, or Splatter Sword, the Kubikiribōchō, or Executioner's Blade, and the Kabutowari, or Helmet Splitter, and with only one member of the Seven Swordsman still loyal to the Village it was decided that until a replacement Wielder for each Blade could be Found John would serve as their Wielder should he prove capable of using them.

So that was how he ended up in this situation he had had no problem dueling the Mists more accomplished Swordsmen with the Kiba. And as an Uchiha John was naturally inclined towards Lightning-Style Chakra, but then again John was also naturally inclined towards Fire-Style, Water-Style and Earth and Wind-Style as well. But more to the point with highly Advanced Skill in Lightning-Style Based Ninjutsu Technique's he coule wield the Kiba with **** Precision and Skill. The Shibuki was by far the most lethal Sword to use, and the Kabutowari was by far the Heaviest and most Cumbersome of them all, but the Kubikiribōchō wasn't that hard to wield, and that concerned John. The Mizūkage had been watching him practice the entire Time he practiced, especially when he wasn't fihring Swordsmen or even a moving Opponent.

John felt that he could love her one day perhaps, if he regained his memory or even if he didn't. He always put on show for the Mizūkage, of course it was still a difficult fight for his opponents even when the Mizūkage wasn't watching, John just upped the ante when she was around.

Within a Month he had mastered the Shibuki and Kabutowari Swords on top of the Kiba he had already perfected. That just Left the Kubikiribōchō, he had requested a week to get a feel for the Weapon before an actual Dueling session, and it was granted. He perfomed simple yet elegant Practice Strikes for about three days before he decided to test the Capability it had when he applied Wind or Lightning-Style Chakra to its Razor-Sharp Edge. But if Being an Uchiha, and an Uchiha from a long line of distinguished Swordsman had taught John anything, it was: That Depending on the Blade, the Blades intended purpose and the Present State of the Blade itself could mean the difference between a highly effective tool and a ineffective tool for the Wrong purpose. He knew that the Kubikiribōchō was a Executioner's Blade, which it was predominantly referred to as, which meant it would have to be very Sharp to achieve its purpose.

However certain Chakra Natures could enhance or cripple a weapins already present properties, for example if one was to flow Earth-Style Chakra into the front of the Hammer of the Kabutowari, it could increase its impact and strength, and Lightning-Style Chakra could Increase the Sharpness and Cutting Power of a Blade, but not as much as Wind-Style could, if not created at a High enough Vibrational Frequency. So he Focused On Lightning-Style first, because he wanted to see how well it would react when the Two were combined.

The Blade didn't handle it well and cracked a little, but was ultimately Repaired after John flowed some of his own natural Chakra into it. Deciding that it would be better to flow the Lightning-Style Chakra into the very tip Blades Edge rather than the whole blade he followed through with it and the Blade faired much better. Wind-Style worked rather well as well, but He was more comfortable with Lightning-Style than Wind-Style, but jot enough to Commit to the Former entirely, ultimately John chose that he would flow Wind-Style into the Blades Edge, but would use it as a Foundation and would Flow Lightning-Style Chakra into the Sharp Bit, using the Wind Chakra to enhance the Blade itself, while the Lightning enhanced the Razor-Sharp Edge.

This worked incredibly well, so when he finally faced off against the swordsmen who weren't afraid to face him, he was more than Ready.